Vehicle raising jack

Abstract: An automatic stabilizing and reinforcing device for vehicle raising jacks having an arm (3) with a stirrup (18), at least one flat front support portion (20), at least one arm (1) to which the jack foot (2) is pivotally connected and a nut (7) in which the jack screw (6) is threaded. The device comprises a convex member (21), rotatably retained and supported on a transverse rod (17) attached to the arm (3) by a hook (23) and by respective end flanges (24). The stirrup (18) is pivotally supported on the convex member (21) and carries a centre plate member (25), located in front of the the stirrup (18) and under the flat front support portion (20) thereof. The stirrup (18) is likewise provided with a downwardly projecting flap (26) attached to the bottom of the plate member (25), in which there is mounted a spring (27) attached at the other end thereof to the arm (3) and holding the stirrup (18) centered.

Description: FIELD OF THE INVENTION The object of the present invention is a vehicle raising jack, such as a "Y" jack, a parallelogram jack with extended lower leg and the like. BACKGROUND OF THE INVENTION Mechanical vehicle raising jacks of various types are known and, among them, the most important are the following: a) the "Y" jack, comprising a column having a ground support foot and a raising arm pivotally mounted to the column at an intermediate height thereon and having a generally channel-shaped end stirrup for supporting the vehicle. For such purpose the latter has respective flanges in the proximity of the corresponding edges of the underside of the bodywork. The said column and arm are linked together by a screw which is threaded into a nut pivotally connected crosswise to the top of the column, while the front end of the said screw is pivotally and rotatably connected to an intermediate point of said raising arm (or the nut could be pivotally arranged on the raising arm and the screw would be pivotally and rotatably attached to the top of the column close to the rear end thereof), while the rear end of the screw is provided with a crank or the like enabling the user to operate the mechanical arm for raising the vehicle and thus be able to replace the corresponding faulty wheel. A jack of this type is described in the patent DE-U-74-14229. b) Parallelogram jack, having four hingedly connected arms and a screw arranged on the diagonal thereof. One of the ends of the screw is threaded in a nut arranged on one of the apexes of the parallelogram, with the other end being attached to the opposite apex, but rotatably. A portion of the screw juts outwards for operation by a crank as in the previously described type. In this jack, the lower apex of the parallelogram has pivotally attached thereto a ground support plate, acting as a foot, and the upper apex of said parallelogram has attached thereto another plate acting as stirrup, for supporting the corresponding part of the vehicle. c) A jack comprising a mechanism having four hingedly connected arms arranged in form of a parallelogram, provided with a screw situated on a diagonal, as in type b), and which is approximately horizontal when the jack is in the position of use and which is operated by a crank or the like. The front end of the screw is threaded in a nut pivotally mounted to the front apex of the parallelogram, while the opposite end of the screw passes through a cross member which is pivotally connected to the rear apex of the said parallelogram. The rear end of the screw is terminated in a rear expansion, which is rotatably supported against the said cross member, there being preferably intermediately situated a bearing to facilitate said rotary support, although the relative positions of said rotary support and of the said nut could, obviously, be reversed. This jack is provided, close to the upper apex of the parallelogram on an extension of the rear upper arm, with a stirrup; while, characteristically, the rear lower arm of the parallelogram, extending from the rear apex thereof, is extended downwardly forming a jack support leg, pivotally attached in turn to a ground support foot. The object of the patent EP-A-0 469 234 is an embodiment of a jack of this kind The different types of known jacks provide different advantages making them particularly useful for particular differentiated applications thereof, in accordance with the technical requirements of the manufacturers of the corresponding vehicles. Nevertheless, the problem raised in general with vehicle raising jacks, insofar as their use by a normal user, who is not specifically versed in this field, nor even in the correct use of the jack to replace a defective wheel of his vehicle, is concerned, consists of ensuring the stability of the ensemble formed by the jack and the vehicle when the former is being used and also of withstanding the mechanical effort required by the vehicle manufacturer as contemplated, among other technical specifications, in his corresponding conditions. Mechanical jacks for raising vehicles are also known to have a support for the underside of the vehicle to be raised. This support is also known as a stirrup (mentioned above) and in certain cases it is fixed, i.e. it is firmly attached to the end of the bearing arm therefor and in other cases it is pivotally mounted about a horizontal pin on the end of said arm which forms the pivot pin for the stirrup, for the better adaptation thereof to the vehicle bodywork during the lifting and lowering operation with the mechanical jack. Where the stirrup rotates relative to the bearing arm therefor about a pivot pin which is parallel to the axis of pivoting of said arm, there is known an embodiment in which said pivot pin is arranged at a certain distance from the support plane of the vehicle bodywork. A further embodiment is also known in which the said pivot pin is supported directly alongside the underside of a flat support portion of the stirrup, such that when the distance between the pivot pin and the lower surface of the vehicle bodywork, where the latter bears on the stirrup, is determined only by the thickness of the said stirrup portion. The known stirrups are normally provided, further to the said flat portion, with a "U" or "V" shaped recess or channel in which a lower flange on the underside of the vehicle bodywork, reinforced to withstand the mechanical stress resulting from being supported on the jack stirrup while the vehicle is being raised or lowered, may be freely housed. The said flange serves to guide the jack stirrup, both when being placed below the bodywork and when being raised or lowered, and prevent untimely slipping, without it reaching down against the bottom of the stirrup channel. Spanish Utility Model ES-U-247.051 discloses a "Y" type vehicle raising jack, like type a) described above, characterized essentially in that the pivot pin of the support plate or stirrup bears directly against the lower side thereof and is arranged approximately horizontally with the projecting formation of the vehicle bodywork floor, i.e., of the underside of the vehicle bodywork where said jack stirrup is placed and adjusted. A jack having a stirrup pivotally mounted on the end of the bearing arm, by way of a pivot pin parallel to the axis of pivoting, may adapt itself better to the relative movement between the vehicle bodywork and said jack, than in the case of a jack having its stirrup fixed relative to the bearing arm thereof. Nevertheless, there are vehicles today where the simple rotation of the jack relative to the bearing arm thereof is not sufficient for the specific suspension, which at times even has a differentiated behaviour between the front wheel suspension and the rear wheel suspension of said vehicles, but rather they require the stirrup to have various degrees of freedom, i.e., various movements to be able to adapt itself suitably to the complex movement of said vehicles when they are being raised or lowered with a mechanical jack, because the suspension gives way in one or another direction other than the one imposed by the mere rotation about a transverse axis relative to the stirrup bearing arm. Furthermore, the vehicle manufacturers require the jacks to be mechanically stronger, partly because of the greater weight of such vehicles derived from the increase of their passive safety (bodywork reinforcement, internal complements, etc), which implies a corresponding reinforcement of the parts of interest of the jack, which is not achieved with the known jacks, unless on the basis of increasing the weight thereof excessively, with a corresponding increase in cost. The applicant is the owner of the Spanish Utility Model ES-U-9300303, the subject matter of which is a stabilizing and reinforcing device for vehicle raising jacks, comprising an arm provided at the end thereof with a stirrup for supporting the vehicle and having the form of a transverse channel with at least a flat front support portion, an arm or column to which the jack foot is pivotally connected and a nut in which the jack screw is threaded. This device is characterized in that the stirrup is provided, at the front support portion thereof, with three downwardly directed projections, one in the centre and the others equidistant therefrom, transversely aligned close to the channel and spaced apart from the respective side edges of said front support portion of the stirrup, such projections bearing against a transverse rod of a length slightly greater than the spacing between the two equidistant projections and attached to the end of the stirrup bearing arm, the latter having attached thereto a central plate member of a width slightly smaller than the spacing between the two upright walls of the end of said bearing arm and is configured with two facing parallel plates, connected by an intermediate plate, forming a lower tubular central portion, situated before the front wall of the stirrup channel and under the front support portion, determining a central recess by which said stirrup if freely pivotally connected to the rod, with a substantial clearance; in that the stirrup channel is provided with a centre front cut-out tab which is directed downwardly and to which there is attached the lower portion of the plate member, also directed downwardly and arranged below the recess; in that there is attached to said lower portion of the plate member the end of a central spring, the opposite end of which is attached to the stirrup bearing arm, keeping the latter centered against the rod in a preset position; and in that the foot is provided with a central recess in which there is located the corresponding lower portion of the arm or column carrying the foot, said recess being crossed, just above, by a transverse rod attached at the front end thereof to the foot and to which said arm is pivotally connected, a spring being disposed between the foot and arm. The said device provides, among others, the advantages of increasing the degree of stability of the jack, reinforcing it at mechanically critical parts thereof and making it easier for the user initially to install the jack under the vehicle bodywork. SUMMARY OF THE INVENTION To overcome the drawbacks and defects of the known mechanical jacks, thanks to the experience of the applicant in this field and bearing in mind their Spanish Utility Model ES-U-9300303, the applicant has devised a vehicle raising jack of the type comprising an arm having at the end thereof a stirrup for supporting the vehicle, said stirrup having the form of a transverse channel with at least one flat front support portion, at least one arm or column to which the jack foot is pivotally connected and a nut in which the jack screw is threaded. This jack is characterized in that it is provided with a member upwardly convex in a plane transverse to the stirrup bearing arm, said member being capable of rotating relative to a transverse rod attached to the end of the stirrup bearing arm, bearing against said rod and being rotatably retained thereon by at least one hooklike section arranged around the rod and by respective end tabs overlapping the corresponding ends of the rod; in that the stirrup is fitted upon and around the convex member, with a substantial clearance in transverse planes relative to the bearing arm thereof and bears on the convex portion of said member, about which it may rock in said planes; in that, furthermore, the stirrup has attached thereto a centre plate member having a width smaller than the gap between two vertical walls of the end of the bearing arm thereof, and having a figure four configuration so as to form a lower tubular central portion, situated in front of the front wall of the stirrup channel and below the flat front support portion thereof, forming a large central recess for the convex member so that said stirrup may rock freely relative thereto on the said planes; in that the stirrup channel is provided with a centre front cut-out tab, extending downwardly and to which there is attached the lower portion of the plate member, likewise directed downwardly and arranged below the recess; in that the end of a central spring is attached to said lower portion of the plate member, the opposite end of which is attached to the stirrup bearing arm, keeping the latter centered against the convex member in a preset position; and in that the foot is provided with a central recess in which there is located the corresponding lower end of the foot carrying arm or column, which recess is crossed, just above, by a transverse rod attached to the front end of the foot and to which said arm is pivotally attached, a spring being arranged between the foot and arm. It is also characterized in that the upwardly convex member is provided with at least one downwardly directed protuberance from the convex portion thereof, which bears on the transverse rod. The vehicle raising jack of this invention, further to the advantages inherent in the vehicle raising jack disclosed in Spanish Utility Model ES-U-9300303, provides, among others, the following advantages: it provides for a more uniform distribution of the load transmitted by the stirrup to the transverse rod attached to the end of the bearing arm, with a progressive transverse rocking or rotation of the said stirrup, further to achieving that the upwardly convex member has a relatively high mechanical strength, both because of the very convex configuration and for having one or more downwardly directed projections forming corresponding reinforcing ribs. The jack of the present invention offers the advantages that will be easily deduced from the embodiment of said jack described in further detail below to facilitate an understanding of the above described features, disclosing at the same time various details. For this purpose, the specification is accompanied by drawings in which, only as an example not limiting the scope of the invention, there is shown one practical embodiment of the said vehicle raising jack. BRIEF DESCRIPTION OF THE DRAWING In the drawings: Figure 1 is a side elevation view of the jack, starting the unfolding thereof beneath the vehicle bodywork (shown schematically in part); Figure 2 is a cross section view on the line II-II of Figure 1, showing a detail of the assembly of the nut; Figure 3 is a view along the arrow A of Figure 1; Figure 4 is a cross section view on the line IV-IV of Figure 1, showing the pivotal connection between the stirrup bearing arm and the column; Figure 5 is a cross section view on the line V-V of Figure 1, showing the stirrup and the assembly thereof; Figure 6 is a cross section on the line VI-VI of Figure 5; Figure 7 is a cross section view on the line VII-VII of Figure 5; and Figure 8 is a cross section view on the line VIII-VIII of Figure 1, showing the lower portion of the jack where it rests on the floor. DESCRIPTION OF ONE EMBODIMENT OF THE INVENTION In accordance with the drawing figures, there is shown therein a "Y" type jack comprising a column 1 (which, in the case of a parallelogram type jack, would be one arm or the extension in form of a leg thereof) to which there is pivotally attached a foot 2 for supporting the jack on the ground and to which column there is pivotally attached, in turn at an intermediate point thereof, a raising arm 3 (carrying a stirrup). The pivotal connection is effected by way of a pin 4 and in such a way that the raising arm is provided at this joint with two cylindrical swagings 5 (Figure 4), which reinforce this part of the arm and determine a larger support surface therefor in its pivotal connection to the column 1. The column 1 and the raising arm 3 are connected together by a screw 6 threaded through a nut 7 (Figures 1 and 2), which in this case is made from plastics material. The screw is provided with two opposite transverse trunnions 8 which are inserted in respective cylindrical swagings 9 in the column 1 so that the nut and, consequently, the screw 6 may rock. Said cylindrical swagings form a reinforcement for the column in this part thereof and a larger support surface for the nut. The column 1 is provided at a position close to the nut 7 with a pin 10 which holds and retains the two vertical walls of the U-shaped section of the column, thereby avoiding any possible separation of said walls in the region of the nut and avoiding, therefore, any separation of the trunnions 8 of said nut, i.e., the separation of the latter. The screw 6 is supported at the front end thereof by support means which may consist of a bearing 11, as shown in Figure 1, or in other suitable means to retain the front end of the screw in position and, in turn, facilitate the rotation thereof relative to its transverse support which, in this example, consists of a transverse shaft-like stop member 12 pivotally mounted in the two vertical parallel walls of the raising arm 3 and against which the bearing 11 abuts, while at the opposite portion it is provided with a sleeve 13 attached to the screw 6 and which holds the arm 3 relative to the front end of the screw and which, at the same time, forms a stop member for the maximum raising of the arm 3 relative to the column 1. The relative position of the bearing or the like and the nut could be reversed, i.e., the latter would be arranged in the place corresponding to the shaft 12 and the bearing would be arranged abutting a pivotal transverse shaft-like stop member, situated in the place occupied by the nut 7 and between the shaft and the projecting rear portion of the screw. A crank 14 is pivotally attached to the rear end of the screw 6, as a means for enabling the user to rotate the screw backwards or forwards, i.e. to raise or lower the arm 3 with the stirrup and, consequently, the bodywork of the vehicle to which it is applied. In this example, the crank 14 is pivotally connected inseparably to the rear end of the screw 6, there being stop members to set the operative positioning thereof, although the screw could be caused to rotate by other means and even these could consist of a separable or demountable connection between the crank or the like and the rear end of the screw. The column 1 is generally U-shaped with the free ends thereof also folded in U in opposite directions, as shown in Figure 4. At the upper end of the column, the web of said U section is partially extended following the oblique cut of said end, forming two tabs 15 (Figure 3), preventing the two vertical walls of the section in this part of the column from moving together, avoiding them pressing on the nut 7, thus preventing the greater force that this would imply because of a certain braking effect on said nut, as well as avoiding any possible deterioration thereof because of such action. The lower end of the column is also provided with a similar arrangement, so that the web of the section is extended and folded along the oblique cut of said lower end and is inserted between the two side walls of the column, preventing them from moving together, i.e., keeping them in the correct position. Obviously, the particular section of the column could be any other with the mechanical strength required for its function, including an embodiment formed by two parallel sections connected by cross members. The raising arm 3 is formed, in this example, by a U-shaped section, although it could be any other shape of suitable mechanical strength. The free end thereof is cut obliquely, so that the web of the section is extended in a bent fashion, between the two vertical walls of the section, to which it is welded at the end. The walls form respective upward extensions 16, to the top end of which there is welded a transverse rod 17 (Figures 1 and 5). The stirrup 18 serves to support the vehicle to which the mechanical jack is applied and has the general shape of a transverse channel, U-shaped in this example (although it could take on a V-shape or any other desirable shape). The lower flange 19 provided on the corresponding underside of the vehicle bodywork may be freely lodged in this channel. Said stirrup is also provided with at least one front portion 20 on which the vehicle body work is actually supported, said portion being substantially flat for such purpose. The jack is provided with an upwardly convex member 21 which may rotate relative to the transverse rod 17. This member bears against said rod thanks to projections 22, two in this example, directed downwards from the convex portion of the member 21, by which it bears against said rod 17. The convex member 21 is retained on the rod by at least one hook-like member 23 (Figures 5 and 7) which, in this example, is disposed centrally and by respective end tabs 24 (Figure 5) which overlap with the corresponding ends of the rod 17. Thus, the convex member 21 may rotate or rock to a certain extent around the axis formed by the rod 17, i.e. around a transverse axis relative to the raising arm 3, without possibility of movement in the transverse direction, due to the presence of the tabs 24. The said convex member abuts said rod by way of the projections 22 which, in turn, reinforce said convex member. Said projections are orientated longitudinally, i.e. parallel to the longitudinal centre line of the raising arm 3. This configuration of the convex member 21 facilitates the rotation thereof relative to the rod 17. The projections 22 could be formed by swagings (like those shown in Figures 5 and 6) or by pieces or inserts fixed underneath the convex member 21. The stirrup 18 has attached thereto, by welding in this example, a plate member 25 the width of which is smaller than the gap between the two vertical walls of the end of the arm 3 carrying the stirrup, so that there is a transverse clearance allowing the stirrup to move in such direction relative to the bearing arm thereof. The stirrup 18 is snugly mounted on and around the convex member 21, but with a substantial clearance in transverse planes relative to the bearing arm 3 thereof and rests against the convex portion of said member 21, relative to which it may rock in said transverse planes, as may be seen in Figure 5. The plate member 25 is formed in two opposite parallel portions, connected by an intermediate portion, determining a figure four configuration (Figure 1) and thereby forming a lower central tubular portion, situated before the front wall of the stirrup 18 channel and below the flat front support portion 20 thereof. This tubular portion forms a central housing with a clearance for the convex portion 21 allowing said stirrup to rock freely relative to said convex member in the said transverse planes relative to the stirrup bearing arm 3. The plate member 25 is attached at the low portion thereof, this time by welding, to a centre front tab 26 cut out from the stirrup channel and which extends downwards, with the plate member 25 extending even further down and having an orifice in which there is engaged the end of a central spring 27, the opposite end of which is attached to the base of the section of the stirrup bearing arm 3, so that, when the stirrup is in the rest position thereof, it retains the latter centred relative to the rod and in a position predetermined by the situation of the lower fastening point of the spring to said arm, further to placing the stirrup in its correct initial position to facilitate the positioning thereof by the user when he offers the jack up to and places it under the vehicle bodywork, apart from acting to eliminate the noise the stirrup would produce when the jack is stored in its place in the vehicle. The above described constitution and configuration of the unit formed by the stirrup 18 and the convex member 21 and its specific assembly relative to the transverse rod 17 allow the transverse clearances of the stirrup relative to the longitudinal centre line of the raising arm 3 thereof, with a progressive tilting and with a joint rotation of said stirrup with its convex portion relative to the transverse rod, thereby facilitating the automatic adaptation of this part of the jack in which the corresponding portion of the vehicle bodywork rests during the raising and lowering thereof, allowing a correct support of the jack on the floor, with a uniform distribution of the load transmitted by the stirrup to the transverse rod, with a progressive transverse rotation or rocking of said stirrup; while obtaining a relatively high mechanical strength of the convex member, both for its very convex shape and for the downwardly directed projections which form corresponding reinforcement ribs for said convex member. To conclude, the constitution, configuration and arrangement of the unit formed by the stirrup 18 and the upwardly convex member 21 allow the stirrup to rock relative to an axis contained in the main median vertical plane of the jack, in combination with a rotation of said stirrup and convex member about the transverse axis formed by the transverse rod 17. The foot 2 of the mechanical jack has a recess 28 (Figures 1 and 8) symmetrical about the longitudinal centre line of the foot, mechanically reinforcing the latter and, also, allowing the transverse pivot pin 29 between the column 1 and the foot 2 to be as low as possible, increasing the stability of the jack. The pin 29 is attached, in this case by welding, to the foot 2, just above it and is provided with a spring 30 wound around the centre portion of the pin. The ends of the spring bear resiliently against the said bottom end of the column 1 and against the foot 2, holding the latter resiliently against the bottom of the column when the jack is not in use and the raising of the column relative to the ground support foot has not yet started, which also automatically predetermines an initial position of placement for the user and, at the same time, avoids possible noise when the jack is stored in the vehicle. The column is provided with two cylindrical swagings 31 reinforcing its two vertical walls at the joint with the foot and determining a larger support surface for the column on the pin 29. The bottom end of the column 1 which, in the initial position of the jack is located in the recess 28, may be provided with abutments 32 to position it relative to the bottom of the recess 28 of the foot 2 and the latter may have tabs 33 for gripping the ground or, in any case, for improving the adherence of the foot to the ground on which it is resting.

Claims: A vehicle raising jack of the type comprising an arm (3) having at the end thereof a stirrup (18) for supporting the vehicle, said stirrup having the form of a transverse channel with at least one flat front support portion (20), at least one column (1) to which the jack foot (2) is pivotally connected and a nut (7) in which the jack screw (6) is threaded, characterized in that it is provided with a member (21) upwardly convex in a plane tranverse to the stirrup bearing arm (3), said member (21) being capable of rotating relative to a transverse rod (17) attached to the end of the stirrup bearing arm, bearing against said rod and being rotatably retained thereon by at least one hooklike section (23) arranged around the rod and by respective end tabs (24) overlapping the corresponding ends of the rod; in that the stirrup is fitted upon and around the convex member, with a substantial clearance in transverse planes relative to the bearing arm thereof and bears on the convex portion of said member, about which it may rock in said planes; in that, furthermore, the stirrup has attached thereto a centre plate member (25) having a width smaller than the gap between two vertical walls of the end of the bearing arm (3) thereof, and having a figure four configuration so as to form a lower tubular central portion, situated in front of the front wall of the stirrup channel and below the flat front support portion (20) thereof, forming a large central recess for the convex member (21) so that said stirrup may rock freely relative thereto on the said planes; in that the stirrup channel is provided with a centre front cut-out tab (26), extending downwardly and to which there is attached the lower portion of the plate member, likewise directed downwardly and arranged below the recess; in that the end of a central spring (27) is attached to said lower portion of the plate member, the opposite end of which is attached to the stirrup bearing arm, keeping the latter centered against the convex member (21) in a preset position; and in that the foot (2) is provided with a central recess (28) in which there is located the corresponding lower end of the foot carrying column (1), which recess is crossed, just above, by a transverse rod (29) attached to the front end of the foot and to which said column is pivotally attached, a spring (30) being arranged between the foot and column. The vehicle raising jack of claim 1, characterized in that the upwardly convex member (21) is provided with at least one downwardly directed protuberance from the convex portion thereof, which bears on the transverse rod (17).

Inventors: CALAFI MOLINE SALVADOR, CALAFI MOLINE, SALVADOR
Applicants: TUBSA AUTOMOCION SL, TUBSA AUTOMOCION, S.L.
Application year: 1994
Main classification: B66F3
IPC codes: B66F3